Sorrie, B.A. 2010. A new variety of purpureum (: ). Phytoneuron 2010-43: 1-6. Mailed 10 September.

A NEW VARIETY OF (EUPATORIEAE: ASTERACEAE)

BRUCE A. S ORRIE University of North Carolina Herbarium North Carolina Botanical Garden Chapel Hill, NC 27599-3280

ABSTRACT Eutrochium purpureum var. carolinianum Sorrie var. nov. is described from the lower piedmont of North Carolina and South Carolina, USA. Its morphological features are compared with the two currently recognized varieties of E. purpureum . KEY WORDS : Eutrochium purpureum var. carolinianum Sorrie var. nov., Asteraceae, Eupatorieae

Atypical specimens of Eutrochium purpureum (L.) E. Lamont (= purpureum L.) found in the lower piedmont of North Carolina and South Carolina, represent a distinct and previously unrecognized variety.

Eutrochium purpureum (L.) E. Lamont var. carolinianum Sorrie, var. nov. Figs. 1, 2, 3. TYPE : USA . North Carolina . Stanly Co.: open powerline southeast of Stony Hill Church, dominated by grasses and herbs, dry soil derived from mafic rock, common, 14 July 2009, B.A. Sorrie 12380 (holotype: NCU).

Eutrochio purpureo var. purpureo similis sed differt foliis late ovatis ad apices obtusis vel acutis, omnino dense lanulosis abaxaliter, marginibus obtuse serratis, et glandibus acheniorum numerosioribus elongatioribus.

Etymology . The varietal name is derived from the two-state region in which the grow. formerly treated within Eupatorium sect. Verticillatum DC. have recently been segregated as the Eutrochium Raf. (Lamont 2006).

Additonal collections examined . North Carolina . Anson Co: upland woods, Pee Dee River, 2.5 mi northeast of Old Sneedsboro, 21 Sep 1956, Ahles 19432 with Leisner (NCU). Cabarrus Co.: low woodland border, 1.2 mi west of jct. of NC 27 and US 601 on NC 27, 23 Sep 1956, Ahles 19754 with Leisner (NCU). Gaston Co.: wooded stream, 4.1 mi east of Gastonia just north of US 29-74 on Ranlo Road, 17 Sep 1956, Ahles 18857 with Leisner (NCU). Montgomery Co.: woodland border, 1.8 mi southeast of Montgomery-Stanly county line (Pee Dee River) on NC 27-73, 6 Jul 1956, Ahles 16290 with Leisner (NCU). Moore Co.: narrow powerline on steep slope, George P Road north of Deep River, 24 Jul 2005, Sorrie 11664 (NCU). Richmond Co.: west of US 1 and east of Pee Dee River, along dirt logging road, disturbed loblolly pine plantation with regenerating hardwoods, 22 Jun 1999, Sorrie 10175 (NCU). Stanly Co.: upland oak woods, 1.7 mi south of Millingport on Millingport-Lambert Road, 6 Jul 1956, Ahles 16213 with Leisner (NCU); north side Jacobs Creek, southwest of SR 1739, frequent in ravine on side of high hill, 17 Oct 2007, Sorrie 12054 (NCU). Union Co.: roadside, 0.8 mi north-northwest of Waxhaw on NC 16, 14 Jul 1957, Ahles, 31387 with Haesloop (NCU); roadside bank on Austin Road (SR 1256), 0.4 mi north of South Carolina line, 12 Jul 2010, Sorrie 12624 (NCSC). South Carolina. Abbeville Co.: roadside, Parsons Mountain, 6 mi south of Abbeville, 29 Jun 1957, Radford 25939 (NCU). Fairfield Co.: roadside at jct. county routes 22 and 28 west of Woodward, 26 Jun 1957, Bell 9354 (NCU). Lancaster Co.: rich mesic woods, 40 Acre Rock, NNE of Kershaw, 6 Jun 1957, Ahles 27456 with Haesloop (NCU). York Co.: wooded Sorrie: Eutrochium purpureum var. carolinianum. 2 slope along Sugar Creek on SC 160, east of Fort Mill, 12 Jul 1957, Ahles 31168 with Haesloop (NCU).

While synonymizing a number of previously named taxa within Eupatorium purpureum L., Lamont (1995, 2006) recognized a widespread variety E. purpureum var. purpureum in eastern North America plus a midwestern variety E. purpureum var. holzingeri (Rydberg) E. Lamont. The latter differs from the typical variety in its “densely puberulent to villous” abaxial sides of leaves (Lamont 1995); it ranges from southern Wisconsin to eastern Nebraska and south to northern Arkansas. In var. holzingeri , pubescence occurs on the abaxial leaf blade surface as well as on leaf veins and is composed of pale translucent-white, lanulose hairs. Pubescence, if any, on abaxial sides of leaves of var. purpureum is restricted to major veins. Lamont (1995, 2006) stated that "West of the Mississippi River (and in the high xeric sand-hills of South Carolina), abaxial leaf faces [of var. purpureum ] are commonly densely pubescent along the major veins."

var. carolinianum var. holzingeri var. purpureum Leaf shape Broadly ovate to Broadly lanceolate to Broadly lanceolate to broadly elliptical, tip narrowly ovate, tip narrowly ovate, tip acute to blunt. acuminate to acute. acuminate to acute. Leaf margin teeth Short, acute to bluntish, Long, sharply serrate Long, sharply serrate not doubly serrate. or doubly serrate. or doubly serrate. Leaf abaxial surface Densely soft lanulose Densely soft lanulose Glabrate, or sparsely on surface and veins. on surface and veins. lanulose on veins; densely lanulose on veins west of Mississippi River. Leaf texture Thickish, +/- rugose. Thin, not rugose. Thin, not rugose. Achene glands at Numerous to abundant, Sparse to moderate, Sparse to moderate, anthesis distinctly long- very short-papillate. very short-papillate. papillate. Range Lower piedmont of Midwestern plains Most of eastern U.S. NC-SC and s Ont.; encompasses ranges of other 2 vars.

Table 1. Comparison of Eutrochium purpureum var. carolinianum , var. holzingeri , and var. purpureum .

The new variety differs in several ways from Lamont’s two varieties (Table 1). Note that var. carolinianum exhibits significant departures from the norm of E. purpureum in leaf shape, marginal teeth morphology, and distribution of vestiture on the abaxial surface. The latter condition is matched only by var. holzingeri , which is disjunct by more than 800 km to the west. These differences give the new variety a very different gestalt than plants of var. purpureum , which grows sympatrically with var. carolinianum but is not known to be syntopic with it. Leaf shape and the somewhat thicker leaf texture are similar to those of E. dubium (Willd. ex Poir.) E. Lamont, but that species' leaves are much more rugose, the leaves have three main leaf veins, and it inhabits wetlands of the coastal plain, not dry uplands of the piedmont. Eupatorium steelei (E. Lamont) E. Lamont has similarly shaped leaves as var. carolinianum , but marginal teeth are sharply serrate, stems are pubescent throughout (vs. glabrous or glabrate below the ), and it occurs in the montane region of the Southern Appalachians.

Sorrie: Eutrochium purpureum var. carolinianum. 3

The shape and abundance of achene glands of var. carolinianum also exhibit significant differences from other varieties of Eutrochium purpureum . In the latter, glands are short-papillate or nearly sessile, and often become difficult to see as the achene matures. In the new variety, the glands appear to be more numerous, are distinctly longer, and remain easily visible throughout maturation of the achene.

A small number of specimens show intermediate character states between var. purpureum and var. carolinianum . These mostly display increased pubescence on leaf abaxial veins and surfaces as compared with var. purpureum , but none of them are as densely lanulose as in var. carolinianum , nor do they have long-papillate glands on the achenes. Leaf shape and dentition correspond with var. purpureum in most specimens. Specimens showing some intermediacy have been seen from Guilford, Iredell, Macon, and Transylvania counties (North Carolina), McCormick County (South Carolina), and Montgomery County (Virginia). Only the McCormick County specimen seems equivocal in identity. The others are outside of the range of var. carolinianum , as outlined here, and are identified here as var. purpureum .

Phenology . As with sympatric plants of var. purpureum , plants of the new variety commence blooming in late June and early July, some three weeks ahead of the two other species of Eutrochium in the general region ( E. dubium and E. fistulosum (Barratt) E. Lamont).

Habitat . Plants of the new variety inhabit dry oak-hickory woodlands and openings in them or through them, such as roadsides and powerlines. Canopy species include Quercus alba , Q. stellata , Carya glabra , C. carolinae-septentrionalis , and Acer rubrum . Understory trees include Cercis canadensis , , Acer leucoderme , Cornus florida , and Juniperus virginiana . The range of the new variety lies mostly within the Carolina Slate Belt; local soils are usually derived from mafic metamorphic rocks and are somewhat acidic to circumneutral. Most populations of E. purpureum var. carolinianum occur in forest openings or clearings, but other populations occur under a dense canopy. In the latter situation, one would expect co-occurrence with var. purpureum , but to date the two taxa have not been found growing together (syntopically). This may be an artifact of limited field work, for var. purpureum also occurs in virtually all of the counties vouchered for var. carolinianum , as evidenced by historical specimens. In any event, a slight shift in habitat preference may contribute to lessened genetic contact.

Phytogeography . Despite its reputation for being floristically uninteresting, the lower Piedmont of the Carolinas (and sometimes extending into adjacent states) features a substantial number of endemic and disjunct taxa adapted to sunny and open habitats, including Acmispon helleri (Britt.) Heller , Helianthus laevigatus Torr. & Gray, Helianthus schweinitzii Torr. & Gray , Silphium terebinthinaceum Jacq., plumosa Small, and Nutt. Other endemics and disjuncts are adapted to more shaded habitats: Carex impressinervia Bryson, Kral, & Manhart, Euphorbia mercurialina Michx., Eurybia mirabilis (Torr. & Gray) Nesom, and Phacelia covillei S. Wats. ex Gray. This suite of taxa suggests an interesting biogeographic history of habitats of the region, which has generated and maintained a distinctive flora.

ACKNOWLEDGEMENTS The continued support of the UNC Herbarium and the Flora of Virginia Project is gratefully acknowledged. I wish to thank curators and managers of NCU and USCH for loans of specimens and access to collections. I thank Guy Nesom for providing the Latin diagnosis.

LITERATURE CITED Lamont, E.E. 1995. of Eupatorium section Verticillata (Asteraceae). Mem. New York Bot. Gard. 72: 1–68. Sorrie: Eutrochium purpureum var. carolinianum. 4

Lamont, E.E. 2006. Eutrochium . Pages 474–478 in Flora of North America North of Mexico. Vol. 21, Magnoliophyta: Asteridae (in part): Asteraceae. Oxford University Press, New York.

Figure 1. Distribution of Eutrochium purpureum var. carolinianum . Var. purpureum occurs throughout the range of var. carolinianum (see text).

Sorrie: Eutrochium purpureum var. carolinianum. 5

Figure 2. Holotype of Eutrochium purpureum var. carolinianum . Sorrie: Eutrochium purpureum var. carolinianum. 6

Figure 3. Leaves of Eutrochium purpureum var. carolinianum showing densely soft-lanulose abaxial surface and veins and thickish, rugose texture.